The Siemens SENTRON 3VA2125-0HN36-0AA0 is a 3-pole molded case circuit breaker (MCCB) rated for 25 A continuous current, built around the ETU350 electronic trip unit. The 440 kA interrupting capacity at 415 V AC tells you it can clear a fault up to that level without the arc re-striking or the case rupturing; at 690 V AC it still holds 187 kA. That's a high-rupturing-capacity breaker suited for large distribution panels or transformer secondaries where fault currents run high.
Ratings that matter for the panel
The 25 A rating holds flat from 40 °C all the way to 70 °C — no derating curve to chase in a warm enclosure. Insulation voltage is rated 800 V, operating voltage 690 V AC, so it's comfortable on 480 V or 600 V class systems.
Footprint and panel fit
Dimensions are 86 mm deep, 105 mm wide, 181 mm tall. That's a standard 3-pole MCCB footprint for the SENTRON 3VA frame size — it bolts into a mounting plate or clips onto a DIN rail (the evidence doesn't specify the mounting method, but the 3VA family supports both).